1. Field of Invention
This invention relates to printing, and in particular to printing with a deformable pad.
2. Prior Art
Pad printing has long been used to apply images to surfaces. This printing technology is especially useful for applying images to uneven, non-flat surfaces of virtually any size. These include products ranging from bottles to cellular telephones to home and industrial appliance panels.
The concept of a deformable pad for printing is taught in our U.S. Pat. No. 6,840,167 (2005). The pad comprises a flat sheet of flexible pad material, such as silicone rubber. It is preferably square, 10 cm on a side, and 1.5 cm thick. The pad can be smaller or larger. The size of the pad is determined by the area and shape of the final receiving surface.
The pad is initially flat and its edges are restrained by a holding bracket. An inkjet head deposits an image on the flat front pad surface. The pad is then forcibly deformed by a ram applied to the opposite side of the pad. The ram preferably has a curved frontal shape. Since the edges of the pad are restrained, the ram forces the pad into a bulged shape. The bulged pad is then brought into contact with the final receiving surface. The previously-applied inkjet image transfers from the pad to the receiving surface. A printed or decorated receiving surface results. The principal advantage of this system is the ability to transfer multi-color images in a single step. This system has been shown to work well, however operation of its pad can be improved for use in certain machine configurations.